#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
struct ListNode
{
	int val;
	struct ListNode* next;
};

struct ListNode* FindKthToTail(struct ListNode* pListHead, int k)
{
	struct ListNode* fast = pListHead;
	struct ListNode* slow = pListHead;

	while (k--)
	{
		if (fast == NULL)
		{
			return NULL;
		}
		fast = fast->next;
	}

	while (fast)
	{
		slow = slow->next;
		fast = fast->next;

	}
	return slow;
}